Wipe the device using Jl_cmder (see the FAQ for info) and then reload the OS (Yellow sticky at the top of the 8500 section). Make sure that you follow all of the directions and be patient, let the device run its course. It can take an hour or longer.

If apploader doesn't connect, see the FAQ for how to get it to connect with Jl_Cmder.

You can also try using BBSAK - BB Swiss Army Knife. Use Google to find a copy.